The CRPRC maintains a colony of over ninety aged (>19 yrs) rhesus macaques as part of a National Institutes of Aging set aside colony program. Currently there are forty one males and fifty females. Animals are maintained on a special geriatric diet program and receive routine physicals by the CRPRC veterinary staff. In 1995 the aged rhesus macaque colony was utilized in research on studies assessing learning and memory, functional imaging of the brain, gene therapy for neurodegenerative diseases, and studies in spontaneous diabetes.